Injection carburetion



Dec. 22, 1964 J. F. ARMSTRONG INJECTION CARBURETION 8 Sheets-Sheet 1 Original Filed June 20, 1955 INVENTOR. JAMES FRED ARMSTRONG vm I um um m Q E O R mm o E o vm mm & o. o O t on O Q HM. R as 4 mm 3 E k y g R MN R w E in 0 mm o o o o R an o o QM MM m M ATTORNEY 1964 J. F. ARMSTRONG Re. 25,701

' INJECTION CARBURETION Original Filed June 20, 1955 8 Sheets-Sheet 2 Q 73- a: FIG.4.

INVENTOR. JAMES FRED ARMSTRONG ATTORNEY G 1 Y 0 3 m0 E 7 t TR N e NT R 5 E E 0 2 V T mM m R in e G s Y H E B m w J n J F ARMSTRONG INJECTION CARBURETION Dec. 22, 1964 Original Filed June 20, 1955 Dec. 22, 1964 J. F. ARMSTRONG Re. 25,701 INJECTION CARBURETION Original Filed June 20, 1955 8 Sheets-Sheet 4 INVENTOR. AMES FRED ARMSTRONG ATTORNEY Dec. 22, 1964 J. F. ARMSTRONG 25,701

INJECTION CARBURETION Original Filed June 20, 1955 8 Sheets-Sheet 5 U) (0 77 A [D Q L C /"C' @QD 66 2:2 F 1 INVENTOR.

JAMES FRED ARMSTRONG AIIORNEY Dec. 22, 1964 J. F. ARMSTRONG INJECTION CARBURETION 8 Sheets-Sheet 6 Original Filed June 20. '1955 INVENTOR. JAMES FRED ARMSTRONG ATTORNEY Dec. 22, 1964 J. F. ARMSTRONG INJECTION CARBURETION 8 Sheets-Sheet '7 Original Filed June 20. 1955 INVENTOR. JAMES FRED ARMSTRONG ATTORNEY Dec. 22, 1964 J. F. ARMSTRONG INJECTION CARBURETION 8 Sheets-Sheet 8 Original Filed June 20, 1955 INVENTOR.

ATTORNEY United States Patent Ofi Fice Re. 25,701 Reissued Dec. 22, 1964 25,701 INJECTION CARBURETION James F. Armstrong, St. Louis, Mo., assignor, by mesne assignments, to ACF Industries, Incorporated, New

York, N.Y., a corporation of New Jersey Original No. 2,785,669, dated Mar. 19, 1957, Ser. N0.

516,358, June 20, 1955. Application for reissue Mar. 18, 1959, Ser. No. 800,354-

83 Claims. (Cl. 123-119) Matter enclosed in heavy brackets II] appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention relates to a fuel flow regulating and distributing device which is responsive to engine requirements to adjust to the fuel-to-air ratio in the charging mixture for an internal combustion piston engine. More specifically, the invention is concerned with devices of this kind in which the fuel is pressurized, measured in accordance with engine requirements, and distributed at points adjacent the intake valves of the several cylinders of the the engine.

In order to perform these necessary functions in the intended manner, the device comprises a plurality of sensing means for engine requirements, preferably responsive to air velocity and pressures in the intake system for indicating the fuel requirement of the engine, and these, in turn, control fuel metering means in passages supplied with fuel under pump pressure and delivering the metered fuel to the engine uniformly with respect to each cylinder to meet these requirements.

This description will be limited to the system as applied to one group of cylinders, but it is contemplated that the combination described, as well as its various parts, or subconrbinations of parts, have other applications in the general art of fuel feeding, since the same principles apply whether the fuel is supplied to one group or several groups of cylinders, or to one or more groups of burners.

According to this invention, charging air is manually controlled, and the sensing means for indicating fuel requirements is responsive, either directly or indirectly, to indicate such variables as engine speed, engine load, and engine operating temperature. The response indications of the sensing means are, in turn, transmitted to control elements for varying the area of metering orifices in a fuel metering part of the device. Fuel under pressure is fed to this fuel metering part of the device by a pump through a pressure regulator. In the fuel metering part referred to, the flow path of the fuel is divided into separately metered fuel distributing circuits connected to separately operate one or more differential pressure operated valves discharging into the engine induction system. Each valve is urged open by the force due to fuel pressure in one of these distributing circuits which delivers fuel for engine charging, and is urged closed by an opposing force due to the action of metered fuel flow into a distributing circuit creating a datum pressure or pressures. These pressures act on opposite sides of a diaphragm in each differential pressure operated valve.

Some of the advantages to be gained from the arrangement of elements in this system may be realized by a recognition of the basic principles involved in their arrangernent. In this system, the same pressure source feeds both of the distributing circuits, and any pressure variations at the source tend to produce porportional pressure variations in each distributing circuit downstream of each metering orifice. The valve construction is such as to maintain a substantially constant difference in pressure between the distributing circuit for engine charging and the one for datum pressure. It follows, therefore, that datum pressure will fix the pressure drop across the metering orifice for the distributing circuit for engine charging.

It is known that fuel will vary directly with variations in orifice area when the pressure drop across the orifice is held constant and the flow coefficient does not change. This principle applied to the present system means that fuel flow in the distributing circuit for engine charging will vary directly with the area of the metering orifice, provided that area of the orifice for the datum pressure distributing circuit is fixed. This principle will hold true regardless of any fluctuation of pressure in the source-t=hat is, in this case, in the pump or pressure regulator.

Since both distributing circuits has a common pressure source and a constant differential pressure is maintained between them on the downstream side of the orifices for both, then variations of the metering orifice. for the distributing circuit for datum pressure varies the pressure drop across all of the metering orifices simultaneously and in a like manner. Because of this pressure drop, the flow through the distributing circuit for engine charging will increase with each increase in the pressure drop across the metering orifice for the datum pressure circuit, and vice versa. f

In the structure hereinafter described, the distributing circuit for datum pressure connects between the fuel pressure source and the intake for the pump, and can be termed a by pass around the pump. This is for purposes of convenience, and is not primarily depended upon to maintain a constant pump discharge pressure as in many of the systems in the prior art. The variations in pressure in the datum circuit can be established by varying the size relation between a metering orifice at its inlet' and one at its outlet. The preferred manner is to vary the inlet orifice area by means of a contoured metering rod supported for longitudinal movement in the orifice. Position of this rod depends upon indications of an engine requirement sensing means responsive to indicate engine load and engine temperature. This Imetering structure is entirely enclosed in a container for the' pressurized fuel, and the indications of the engine condition sensing means are transmitted into rod movement by means of a magnetic clutch. This type of transmission avoids the friction inherent in diaphragms, seals, or packings, and increases the sensitivity to changes in engine requirements. Datum pressure changes are effected in the datum circuit during engine operation in response to indications of the sensing means, and these directly affect the amount of fuel discharged to the engine.

In the preferred form of the invention, the fuel distributing circuit for engine charging has individual branches with individual metering orifices, and each branch connects to one differential pressure operated valve. The area of these orifices is controlled by suitably contoured metering rod-s supported for movement in unison by indications transmitted from an engine requirement sensing means. Preferably this sensing means is one responsive to rate of air flow through the induction system or its equivalent engine speed combined with throttle opening, which are variables determining this function. The rods are enclosed within a fuel pressure container, and transmission between the sensing means and rods is also by a magnetic clutch.

In a system having a constant pressure drop, the use 01 mete-ring rods has a definite, practical utility. Thus where the shape of the mixture curve for a particular engine is known, as well as the limitsof maximumroc travel in the orifices, the procedure for calibration is simplified. By calculation, rod size can be determine( for points between these limits to correspond with the rate of flow indicated by points on the curve, and the rod ther contoured. The flow curve will be reproduced in th metering for any constant pressure drop which is fixe( by constant metering of datum pressure and can be raised or lowered between any desired limits by variations in datum metering. These limits, in turn, can be readily fixed by a manual adjustment applied in a novel way to determine the upper, or full rich position of the cuwe, and the lower or part-throttle position of the curve.

In order to provide for satisfactory operation when the engine is cold, the system includes a temperature sensing means for-elfecting datum pressure metering to enrich the mixture and increase the manually controlled charging air for fast idle.

Also incorporated in the system is an unloader system operative to cut ofi the fuel supply and give maximum air flow to the engine during engine starter motor operation.

This system, including its several features, as above described, may take various forms. By way of example, one of these forms is illustrated both diagramatically and structurally in the accompanying drawings, in which:

FIG. 1 is a schematic showing of one embodiment of an engine charging system illustrating the parts of the system in the positions assumed at engine idling speeds and normal operating temperatures.

FIG. 2 illustrates the position of parts of the flow sensing means during part-throttle operation of the engine at full load and normal operating temperatures.

FIG. 3 shows the parts of the system during part-throttle operation and operating temperatures below normal.

FIG. 4 shows the parts of the system in the positions which they will assume at engine idling speeds and at engine temperatures below normal.

FIG. 5 is a schematic illustration of the de-icing structure, and illustrates the air conduit body in cross-section, the heating passages, and the control for heated air positioned to supply heated air to the air conduit body.

FIG. 6 illustrates the de-icing structure with the controls in a position to by-pass the heated air around the air :onduit body passages.

FIG. 7 is an elevational view, in section, of the heat- Ing circuit diagrammatically illustrated in FIGS. 5 and 6.

FIG. S'is a top plan view of a structure embodying the ill and fuel metering means schematically illustrated in he prior figures of'the'drawing."

FIG. 9 is a bottom plan view of the same structure.

FIG. 10 is a side elevation of the structure shown in IG. 8 as viewed from the left.

FIG. 11 is a side elevation of the structure shown in 16. 8 substantially on line 11-11.

FIG. 12 is a vertical section of the cap and thermostatic oil of FIG. 11. I

FIG. 13 is a side elevation taken substantially on line .3-13 in FIG. 8 with parts broken away and in section 0 illustrate details of the construction.

FIG. 14 is a side elevation with parts in section along he line 14-14 of FIG. 8, and a wall plate removed to how the underlying structure.

FIG. 15 is a side elevation with parts in section along 1e line 15-15 of FIG. 8.

FIG. 16is a detailed view of the fuel distributing cap iowing the arrangement of the individual fuel line conections.

FIG. 17 is an interior view of the mechanism within the etachable housing in FIG. 8 taken substantially on line 7-17 of FIG. 8.

FIG. 18 is a fragmentary side elevation with parts reioved and in section along the line 18-18 of FIG. 8.

FIG. 19 is an end elevation of the structure in FIG. 8 viewed from the bottom of the drawing towards the IP,

FIG. 20 is a view, in section, of an engine intake pas- .ge showing the location and arrangement of the injecm nozzle.

AIR INDUCTION SYSTEM FIGS. 1 to 7 of the drawings schematically illustrate one rm of an engine charge forming device embodying the AIR FLOW SENSING DEVICE Within the air conduit body B is a balanced butterfly air valve 37 mounted on a shaft 36 journaled for rotation in the side walls of the air conduit body. Mounted on one side of the air conduit body is a housing which is divided into a pair of chambers 41 and 42 by a diaphragm 40. Chamber 41 is connected with air conduit B through a port 44 in the wall thereof anterior of the air valve 37. A tube 45 connects the opposite chamber 42 with the air conduit B posteriorof the air valve 37. The rod 39 interconnects the air valve 37 and the diaphragm 40 in such a manner that pressures acting on the diaphragm in the chambers 41 and 42 will position the valve 37 angularly in response to pressures sensed on opposite sides of the valve through the port 44 and the tube 45. A spring 43 calibrated to give the proper resistance urges the valve 37 to the closed positio The air valve diaphragm arrangement above described is operated by differences in pressure in the air conduit B as sensed by the ports anterior and posterior of the valve. It will therefore take up a position in response to this sensing means which will indicate directly by its angular displacement the rate of air flow passing through the air conduit B, and, since the rate of air flow is dependent primarily upon engine speed and throttle opening, the angular position of the valve 37 when balanced in the air flow through the conduit B will be an indication of these two engine variables.

In order to provide for some adjustment of the angular indication of the valve 37 in response to these variables, air conduit body B is provided with a by-pass and an adjustable metering screw 78. By adjusting the rate of air flow through the by-pass 80, the indication of the air valve 37 to rate of air flow can be changed to suit the calibration of the metering means for fuel which it controls.

The calibration of the spring 43 is such that the angular position assumed by the valve '37 is determined by only a slight pressure ,change on its opposite sides, such as a constant pressure drop of 8 or 10 inches of water.

Below the air valve 37 is a manually controlled throttle valve 50 mounted on a shaft 51 journaled in the walls of the conduit B. Operating lever 52 is secured to shaft 51, and provides for attachment of the usual manual control.

ENGINE LOAD AND TEMPERATURE SENSING DEVICE Below the throttle 50 is a port 116 in the wall of the conduit B connected by a line 84 with a cylinder 83 below a piston 82 in the cylinder. Cylinder 83 is open at its upper end to a chamber (not shown) containing the thermostatic enrichment coil spring 76. This chamber is, in turn, connected to a source of engine heat. The difference in pressure on opposite sides of the piston 82 during the engine operation at idle and normal cruising speed of the vehicle causes the piston to assume the position shown in FIG. 1, compressing the spring 85 beneath the piston.

This pressure difference also causes a continual flow of air from a source of heat 108 in FIG. 5 through the thermostat chamber enclosing the thermostatic enrichment coil spring 76 past the piston through the bypass 101 and into the conduit B by way of line 84 extending to port 116. Y

Movements of the piston 82 Within the cylinder 83 are communicated through a piston rod connected with a lever 70 to a shaft 65 upon which is mounted a lever 68 having an offset lug 71 threaded to receive adjusting screw 72. Thermostatic enrichment coil spring 76 has its inner end concentrically arranged with the shaft 65 and secured to some fixed portion within the chamber. Its outer end projects radially of the shaft 65 into abutting relation with the inner end of screw 72 and, at normal engine operating temperatures, contacts the inner end of screw 73 'threadedly mounted within a fixed portion 74 of the chamber structure. The radial extension 75 also forms an abutment for the lug 99 on the lever 68.

This structure forms a sensing means connected with the air conduit B which will indicate by position of the shaft 65 the amount of load under which the engine is operating. Likewise, since the thermostat 76 is heated preferably from a source 108 on the engine, shaft 65 may also take up a position responsive to both engine load and engine temperature.

At normal engine load and normal engine temperatures,

the parts will assume the position as shown in FIG. 1,-

with the piston 82 depressed and adjusting screws 73 and 72 engaging the radial extension 75 off the thermostat. As engine load increases, however, spring 85 will expand due to the decreasing force exerted on the piston 82 by the difference in pressure on its opposite sides. Movement of the piston in response to the spring engages the lug 99 with the radial extension 75 on the thermostat 76, thereby rotating the shaft 65 to a position indicating a change in the fuel requirements of the engine from part-load to full-load. The parts will then take the position shown in FIG. 2. a

The construction of the thermostat 76 is such that decrease in temperature tends to rotate the radial extension 75 in a counterclockwise direction to a position such as shown in FIG. 3 and FIG. 4. This, in turn, produces an angular displacement of the lever 68 in the same direction, and rotation of the shaft 65 to another position or positions indicated by the engine temperature. Where, at the same time, the engine load is heavy, the position of the parts will be such as that indicated in FIG. 3, which illustrates the extreme displacement of the lever 68 in a counterclockwise direction, and similar movement of the shaft 65.

Where the engine load is light and engine temperature is low, the position of the parts is illustrated in FIG. 4, wherein the piston 82 has compressed the spring 85 to place the shaft 65 in a new position indicating light load at low temperature.

Shaft 65 also carries a fast idle cam 64 which cooperates with a finger on lever 66 secured to the manually operated throttle shaft 51 so as to open the throttle 50 slightly in FIG. 4 at low engine temperatures to increase engine idle speed.

Shaft 65 and its temperature and pressure control form a sensing means which will indicate by the position of the shaft 65 both load and temperature condition of operation for the engine, and indications of this sensing means are transmitted to the fuel metering system by the position of shaft 65.

Air conduit B has a by-pass 79around the manual throttle 50 controlled by an adjusting screw 77. This control provides for regulating the air flowing past the manual throttle when in the idle positions. As will be readily recognized, screw 77 corresponds in function with the ordinary mixture regulation screw in the conventional carburetor.

FUEL METERING SYSTEM As will be described hereinaftermore fully, positions of the indicating means controlled by the sensing means are transmitted to position fuel metering mechanism within a fuel metering part indicated in the drawings as A. The fuel supply to the metering part A is by way 6 of a line 19 from a suitable source of fuel to pump P, and thence, by way of line 20, to a pressure regulating device 22. Fuel entering the regulator passes first through a filtering element 21 to a control valve 22b operated by pressure downstream of the valve 22b acting on a diaphragm 220 against the resistance of a calibrated spring 22d. Suitable mechanism is provided for mechanically connecting the valve 22b to be operated by movements of the diaphragm under the influence of pressure of fuel downstream of the valve acting in one direction and atmospheric pressure and spring 22d acting in the opposite direction. Regulator 22 is preferably adjusted to deliver about twenty-five pounds of gauge pressure through the line 20a to the chamber'enclosing the fuel metering part indicated as A. Because of features of the system which are inherent in the arrangement of valves and hydraulic circuits, it is not necessary that the pressure regulator 22 maintain a precisely constant pressure in the metering part of the metering chamber. Accurate metering does not depend upon accurate pressure regulation in this part of the system.

Within the fuel metering chamber A is a fuel charge control mechanism comprising one or more metering orifices 23 receiving one or more contoured metering rods 33 mounted on a carriage 34 for movement within the metering orifices 23. Each orifice 23 controls the flow to a separate fuel charging line 24 connecting at its oppo site end to a fuel nozzle 25. Preferably, there are as many metering orifices 23, metering rods 33, and fuel charging lines 24 connecting with nozzles 25 as there are cylinders in the internal combustion engine, but it will be appreciated that alternative arrangements are possible wherein one metering orifice and rod may control the supply to one or more fuel nozzles 25. Likewise, the

number of fuelnozzles 25 may vary from one to a number corresponding with each of the cylinders. Proper location of the fuel nozzles is a matter of choice in order to obtain good fuel distribution between the several cylinders of the engine. Fuel metered through the orifices 23 into the line or lines 24 is eventually fed directly to the induction system of the engine from fuel nozzles 25. Consequently, these elements form the distributing circuit for engine charging. The position of the carriage 34, and consequently the position of the metering rods 33, is determined by the position of shaft 36 through the magnetic clutch 35, one part of which will take a position indicated by the air valve 37 acting in response to engine air requirement.

Also within the fuel metering part A is a metering orifice controlled by a metering rod 87. The position of this rod within the orifice determines the rate of flow from the chamber A to a distributing system for datum pressure. This circuit includes a plurality of lines interconnecting each of the fuel nozzles 25 and discharging through a line 58 and variable orifice to 'the supply line 19. Fuel is supplied to this circuit from the metering orifice 55 through a connecting line 56 between the orifice and the lines of the distributing circuit.

The flow restriction 60 comprises a seat in the outlet controlled by a needle valve 123 actuated, in turn, by fuel pressure in the chamber 122 acting on the diaphragm 126 against the resistance of spring 121 and atmospheric pressure communicated to the chamber 120. Pressure in the distributing circuit for datum control is increased or decreased, as the case may be, by adjusting the area of the orifice 55 by rod'.87. The larger the area of the orifice, the greater will be the datum pressure, and vice versa. boxes, packing glands and diaphragms, position of the needle 87 is controlled by a magnetic clutch which transmits the motion of the shaft outside the fuel chamber A to the needle 87. The position of the shaft 65 indicates the response of the engine sensing means for load and engine operating temperature, as above described.

In order to avoid the friction inherent in stuffing 7 FUEL NOZZLES In a fuel feeding system using more than one fuel nozzle, the particular construction affords, not only uniform delivery between the nozzles, but also uniform fuel metering to each. The valve 25 has a casing 27 forming a chamber 30 at one end, and an extension 25a with a seat for the valve stem 29. The extension 25a is suitably secured in the engine cylinder head in a position to discharge adjacent the intake valve 26. Diaphragm 28 is secured to the stem 29 and forms a closure for the chamber 30. A cap 57 secures the diaphragm in place and houses a coil spring 31 urging the valve 29 on its seat. The diaphragm and spring con-trol of the fuel nozzle control valve assembly is so designed that a difference of fuel pressure of about a half-pound'on opposite sides of the diaphragm is necessary to unseat the valve 29.

Each line 24 in the distributing circuit for engine charging connects with each chamber 30 in each fuel nozzle, so that engine charging pressure is applied beneath the diaphragm 28 in a valve opening direction. Each chamber within cap 57 of the fuel nozzle control valve is, in turn, connected with the distributing circuit containing datum pressure, so that datum pressure in this chamber opposes movement of the valve 29 in the opening direction. This particular pressure acting to close the valve 29 is, in turn, determined as a function of the area of the metering orifice 55 by the position. of the needle valve 87. Increases in area of the orifice 55 will be accompanied by increase in datum pressure, and this, in turn, decreases the pressure drop across orifices 23 in the distributing circuit for engine charging to decrease the flow of fuel to the engine regardless of the position of the metering rods 33.

Decrease in the area of the metering orifice 55 by movement of the rod 87 into the orifice decreases the datum pressure, and thereby the resistance of the valve 29 to opening, thereby increasing the pressure-drop across the orifices 23 to increase the fuel flow to the distributing circuit for engine charging. It will be appreciated that datum pressure changes produce an inverse effect, increasing the pressure drop across the orifices 23 with decrease in datum pressure, and decreasing the pressure drop across the orifices 23 with increased datum pressure. Because the flow across the orifices 23 will vary directly with the pressure drop, otherthings being constant, then it becomes apparent that the sensing means forengine load and temperature, which determines the datum pressure, will have an indirect control through its own hydraulic linkage with the fuel nozzles 25 to vary the fuel delivered to the engine.

Where there are a multiplicity of fuel nozzles 25, each is connected to the datum pressure distributing circuit, and, due to this hydraulic interconnection, there will be a positive force acting on each diaphragm which is substantially equal in each nozzle.

The second function performed by the fuel nozzle control valve is that of maintaining a constant pressure drop between the distributing circuit for engine charging and the distributing circuit for datum pressure. As stated heretofore, it requires approximately a half-pound difference in pressures on opposite sides of the diaphragm 28 to open the valve 29. Any increase in this difference in pressure due to increases in pressure in the'distributing circuit for engine charging will produce a displacement of the valve 29 in an opening direction so as to restore the pressure difference by increasing the discharge from the fuel nozzle. 7 Of course, the reverse of this action will take place, since any decrease in this pressure differential allows the valve 29 to close and decrease the flow.

Both orifices 23 and 55 are fed from the same pressure source, and it therefore becomes apparent that fluctuations in this pressure sourcewill be reflected downstream of the orifices in proportional amounts. When this depends wholly upon the pressure difference between the lines in the distributing circuits for engine charging and datum pressure. Likewise, since the How from the nozzles remains unaffected, it follows that the pressure drop across the orifices 23 remains a constant for any given position of the needle valve 87 regulating datum pressure, and the entire fuel feeding system will remain in balance due to the fact that the fuel nozzle control valve assemblies regulate the pressure downstream of the orifices 23 to maintain a constant pressure drop therein.

Unlike prior systems, no attempt is made to hold the pressure upstream of the metering devices constant by a valved by-pass connecting opposite sides of the orifices. The defect in such systems is apparent because a pressure change must occur downstream before correction can be made upstream of the orifice. It follows that the metered flow must change before correction is made.

The datum pressure distributing circuit described herein amounts to a by-pass, but its function in the combination is distinct from that in prior devices in this respect. It is not primarily intended to function as a pressure regulator for the chamber enclosing metering part A. Such an effect, if any, is merely incidental in its operation.

ENGINE TEMPERATURE AND DE-ICING CIRCUIT FIGS. 5 to 7, inclusive, are viewsillustrating schematically in'horizontal and vertical section the system for operating the engine temperature sensing thermostat 76 combined with a system for applying heat adjacent the manual throttle 50 to avoid icing. In this heating system, a port adjacent the entrance to the air conduit body is connected by a line 111 with a chamber 106 containing a thermostat operating a valve 114 for closing a by-pass passage 112. Chamber 106 is connected by a line 107 with a heater 108 disposed within the water jacket or exhaust manifold 109 of the engine. The heater is connected by way of branch passages 103 and 110 to the thermostat chamber 102 and the passage 113 within the air conduit body B. Chamber 102 contains thermostat 76 and also the piston 82 operating in the cylinder 83 which, in turn, connects with an arm 70 on shaft 65 (not shown). A'by-pass 101' controlled by the position of the piston 82 interconnects the chamber 102 with the line 84 leading to a port 116 in the air conduit body B posterior of the throttle 50. The operation of the thermostat and piston as an engine temperature and load sensing means has already been described and will not be repeated here except insofar as to explain the response of thermostat 76 to engine temperature.

Passage 113, which also receives heated air, is located ad acent the edge of throttle 50, and discharges through a port at the edge of the throttle.

F IG. 5 illustrates the position of the parts when the engine is cold. During this engine condition, thermostat 105 is uncoiled, closing valve 114 and shutting off the by-pass line 112 communicating with the heating passage 113. Similarly, thermostat 76 is uncoiled, rotating the shaft 65 counterclockwise, and raising the piston 82 to its extreme upper position in the cylinder 83.

When the engine is started, suction at the port 116 will be sufiicient under any condition of engine operation to cause piston 82 to compress spring 85 so as to open the by-pass passage 103 to some extent. Communication is then established from the port 116 to the chamber 102, and thence to heating element 108. The suction at port 116 will cause a flow of air into thermostat chamber 106 from line 111, and from thence into line 107, heater 108, and thermostat chamber 102. If the engine is operated with the throttle 50 slightly open, port 115 will be posterior of throttle 50, and suction at the port 115 willcause a flow of heated air through the line 110, passage 113, to

the port 115.

FIG. 6 indicates the position of the parts during operatlon of the engine at normal tempertures. Under these 9' conditions, under-hood temperatures will be suflicient to raise the temperature of the air enteringthe thermostat chamber 106 from the line 111, and thermostat 105 will respond to open the valve 114 to some degree. When this valve is open, the air fiow from the chamber 106 will be divided between the line 107 and the line 112. Some of the air entering the chamber 106 will pass through heater 108, while the remainder will pass through line 112 to passage 113, where the flow will be divided again with some flowing directly to the port 115. The remainder circulates through the passage 113 to line 110 to mix with the heated air from the heater 108 passing through the line 103 to the thermostat chamber 102. This will modulate the heating effect on the thermostat 76 so as to prevent strain on the thermostat from overheating. Heated air from the chamber 102 passes through the cylinder 83 by way of by-pass 101 to the port 116. This will continually apply some heat to the thermostat 76 after the engine has reached normal operating temperatures.

FUEL CHARGE v UNLOADER Referring to FIG. 1, the unloader system provided for the fuel metering system has a valve 59 located in the datum pressure by-pass line 58 which is operated only at substantially wide-open throttle positions during the starter motor operation for cranking the engine. Valve 59 is maintained in the open and inoperative position by a spring 91, and closed on energization of a solenoid 90 connected by a line 92 between the starter switch 93 and the starting motor 95. The starting switch 93 is connected directly with the primary of a battery 94. The solenoid 90 is connected with ground through a line 96 connecting with unloader switch 97. This switch 97 is so located as to be closed by action of a lever 98 on the throttle shaft 51 when the throttle 50 is moved manually to nearly wide-open position.

With both switches 93 and 97 closed, the engine is cranked, and, simultaneously, valve 59 closes. As a result, datum pressure becomes equal to the charging pressure in the metering part A, and, since a half-pound differential or more is necessary to open the fuel nozzles 25, all fuel flow through the nozzles is prevented. This operation becomes necessary only in case the engine is flooded for some reason or other and the mixture 'too rich in the cylinders to be ignited. With the fuel supply shut off, air alone is pumped through the induction system, which will dilute the mixture in the engine cylinders, removing the excess fuel, so that the mixture in the cylinders becomes ignitable. As soon as the engine fires and starter. switch 93 is open, the circuit will be broken, and valve 59 will open, due to the action of spring 91.

OPERATION FIG. 3 illustrates the approximate position of the parts during cranking of the engine at low temperatures. With the throttle 50 partly open to admit sufiicient air before starting, air valve 37 will assume some such position as illustrated at the cranking speed of the engine. The position of the valve 37 is indicated by shaft 36, which, in turn, is transmitted through the magnetic clutch 35 to correspondingly position the metering rods 33 in the orifices 23. This will open the orifices 23, and fuel pressure within the chamber A is communicated by way of these orifices to the distributing system for engine charging and fuel nozzles 25.

On the other hand, the temperature of the engine, together with the lack of any suction below the throttle, permits the thermostatic enrichment coil 76 to unwind to its full extent. The position of the shaft 65 in response to thermostat action is transmitted through the magnetic clutch 86 to the datum pressure metering rod 87, which will substantially close the orifice 55. Datum pressure is thereby reduced and, accordingly, the pressure drop across the orifices 23 is correspondingly increased to increase the amount of fuel delivered from 10 the fuel nozzles 25. A rich mixture suitable for starting the engine cold results.

FIG. 4 shows the position of the parts when the engine starts. After the engine starts and throttle valve 50 is closed, engine suction acts to compress spring by forcing the piston 82 downwardly from its position shown in FIG. 3. This action, in turn, is transmitted to the shaft 65, arm 68, and adjusting screw 72, to wind up the thermostatic enrichment coil 76 until equilibriumis reached between the forces acting on piston 82 and the forces acting in the opposite direction in spring 85 and thermostatic enrichment coil 76 to give a suitable mixture during idling operation of the cold engine. In FIG. 4, arm 66 is displaced by cam 64 to crack the throttle 50 and increase engine speed during the warmup. Of course, the balance in the system can be changed in order to give a full-rich mixture in case it is desirable to operate the engine at full load when cold. Under these conditions, the piston 82 would assume some position between that illustrated in FIG. 3 and that illustrated in FIG. 4.

The position of the parts during idling at normal temperatures. is illustrated in FIG. 1, and a description of the operation under these conditions is believed unnecessary in view of the above remarks.

FIG. 2 illustrates operation of the engine at substantially full throttle under heavy load or full load conditions. The decrease in difference in pressure operating on opposite sides of the piston 82 allows spring 85 to rotate shaft 65, lever 68, until lug 99 abuts the radial extension 75 on the thermostatic enrichment coil. The position indicated by the shaft 65 is transmitted through the magnetic clutch 86 to move metering rod 87 into orifice 55, thereby increasing the pressure drop at this point. Since the corresponding effect will be had in the orifices 23, fuel flow is stepped up in the distributing system for engine charging to increase the fuel-air mixture ratio, and this will take effect regardless of the position of the metering rods 33. This automatic-stepup arrangement can operate at any engine speed, and is useful through substantially the entire range of engine speeds to meet the fuel requirements of full engine load.

STRUCTURAL FORM OF AIR INDUCTION SYSTEM FIGS. 8 to 20 illustrate an actual structure based on the system above described. Where possible, the same reference characters will be used for the same parts indicated in the prior figures of the drawings.

According to FIG. 8, the air conduit body B is constructed as a unit with the fuel metering part A. For purposes relating wholly to structural design, the fuel metering part is divided into two castings, shown in the drawings as A and C. The air metering parts of the structure are mounted within the passage through the air conduit body B, theentrance to which is shown in top view in FIG. 8. The bottom view in FIG. 9 illustrates a flange 201 surrounding this passage and provided with suitable bolt holes 202 by which the unit can be securely attached to a branched manifold extending to a number of cylinders in the internal combustion engine. For example, each of the branches connects with an intake port 204 in the cylinder head of the engine as illustrated in FIG. 20. Intake passage 26a communicates with the intake port 204 and is controlled by the intake valve 26 guided for movement within the cylinder head 207.

Adjacent each intake valve 26 and projecting into the intake passage 26a is a mounting tube 208 having a flange and coupling 209 and 210. Casing 27 of the fuel nozzle 25 has suitable threads for engaging the threaded coupling 210 for securing the fuel nozzle 25 in position withthe extension 25a positioned adjacent the intake valve 26 and discharging into the intake passage 26a.

The outlet of the air intake passage in the air conduit body B is controlled by a manually operated throttle 50 mounted on a shaft 51 journalled in the walls of the air conduit body B. Manual operation of throttle 50 iseifected through suitable connections with a throttle lever 52 shown in FIGS. and 11.

STRUCTURAL FORM OF AIR FLOW SENSING DEVICE Within the air conduit body B is a balanced butterfiy air valve 37, shown in FIG. 8, journalled for rotation in the side walls of the air conduit B on a shaft 36. On one side of the air conduit body B is a housing 214 provided with a cap 216, as shown in FIG. 14. This housing is divided into a pair of chambers 41 and 42 by a diaphragm 40. Chamber 41 is connected with air conduit B through a port 44 in the Wall thereof anterior of the air valve 37. A tube 45 connects the opposite chamber 42 with the air conduit B posterior of the air valve 37. Opcrating rod 39 (FIG. 8) connects between a bracket 217 on air valve 37 and diaphragm 40 in such a manner that the pressures acting on the diaphragm in the chambers 41 and 42 will position the valve 37 angularly in response to pressures sensed on opposite sides of the valve through the port 44 and the tube 45. In order to guide the rod 39 within its proper path of movement and free of frictional engagment with the parts of the structure, the guide link 218 is provided connected between a pivot on the housing and a pivot on the operating rod 39. Spring 43 is calibrated to give the proper rate of resistance, and urges the valve 37 to the closed position.

In order to coordinate displacements of the valve 37 with similar displacements in the fuel metering system which it controls, an air adjustment is provided in the form of a bypass 80 (FIG. 8) and an adjustable metering screw 78 (seealso FIG. 11). By adjusting the screw 78, indication of the air valve 37 to the rate of air flow can be changed to suit the calibration of the metering means for fuel which it controls.

As explained above, the calibration of the spring 43 is such that the angular position assumed by the valve 37 is proportional to the rate of air flow through the air conduit body B. Preferably, the pressure drop required to precisely position the valve 37 is held to a maximum of eight or ten inches of water pressure drop across the valve.

ENGINE LOAD AND TEMPERATURE SENSING DEVICE Located below the throttle 50 in FIG. 9 is shown a port 116 in the wallof the conduit B connected by a series of passages 84 (see FIG. 8 and FIG. 18) with a cylinder 83 below a piston 82 in the cylinder. The cylinder 83 opens at its upper end into chamber 102, which, in turn, is provided with a connection 103 from a source of heat on the engine, as will later be more fully described. Within the chamber 102 is a thermostat enrichment coil spring 76. The inner end of the thermostat enrichment coil has a diametrically extending end 222 (shown in FIG. 19) secured in a slotted stud 223 integral with cover plate 224 enclosing chamber 102. The clamp and screw arrangements 225 frictionally hold the cover 224 in any adjusted position, and the cover 224 is provided with indexing means 226 to indicate its relative position on the chamber and the adjusted tension on the thermostat enrichment coil 76.

The difference in pressure on opposite sides of the piston 82 during the engine operation at idle and normal cruising speeds of the vehicle causes the piston to as- ;ume the position shown in FIG. 18, for example, compressing the spring 85 beneath the piston. This pressure difference also causes a continual flow of air from a iource of heat through the connection 103 into the thernostat chamber enclosing the thermostat coil 76 past :he piston, through the by-pass 101, and into the coniuit B by way of the passages 84.

Movements of the piston 82 in response to the opposmg forces of spring 85 in one direction and suction in the opposite are communicated through a connection with a lever 70 to a shaft 65 carrying a lever 68 with an offset lug 99. The outer end of the thermostat enrichment coil 76 has a radially directed end which, at normal operating temperatures of the engine, moves into abutting relation with the inner end of screw 72 and the inner end of screw 73 threadedly mounted within a fixed portion 74 in the wall of the chamber structure.

This structure forms a sensing means connected with the air conduit B which will indirectly indicate by position of the shaft 65 the amount of load under which the engine is operating, or both load and temperature, all in a manner described heretofore.

Shaft 65 carries a fast idle cam 64 which cooperates,

. through a push rod mechanism 230, with a finger 66 secured to the manually operated throttle shaft 51. Around the rod 230 is a spring 231 constantly urging the rod outwardly, away from the cam 64. A pin 232 mounted in the housing has an end projecting through a slot in the pin 230 to limit its travel in either direction.

tor structure is a needle valve the threaded connection 20 Suitable adjustment is provided in the length of the push rod 230 by an adjusting screw 233 in abutting relation with the finger 66. When the throttle is open, the pin is urged outwardly, away from the cam 64, so as not to interfere with the action of the sensing means on the position of the shaft 65. Positions of the shaft 65 Will indicate the variables of-load and temperature and transmit these indications through a magnetic clutch 86 (shown in FIG. 8) having magnets disposed on opposite sides of a non-magnetic wall in the closed chamber C containing the datum pressure control metering.

The passages 79 and 84 have a common outlet 116, but the fiow through passage 79 is separately regulated by a metering screw 77 (as shown in FIGS. l3, l5 and 18) by Which the amount of air lay-passing the throttle can be manually adjusted. The effect produced by adjustments of screw 77 will correspond in function with the ordinary mixture regulation screw in the conventional carburetor.

STRUCTURAL FORM OF THE FUEL (METERING SYSTEM Charging fuel metering-The fuel metering mechanism is contained within two communicating but enclosed chambers A and C. The fuel supply for the metering part A is connected to a filter chamber 240 at (as shown in FIG. 8). As explained heretofore, the source of fuel pressure may be a pump, the output pressure of which is regulated by the mechanism indicated as 22. Within the regula- 22b controlled through a leverage by diaphragm 22c secured in place by a cap 241 and suitable screws 242. The cap of the regulator contains a spring 22d which acts in opposition to fuel pressure beneath the diaphragm 22c. Regulator 22 is preferably adjusted to deliver about twenty-five pounds of pressure to the fuel metering parts A and C. Passages Ztla connect the chamber A of the fuel metering part and the chamber C of the fuel metering part with the pressure regulator 22 (as shown in FIGS. 13 and 15, respectively.

Within the fuel metering chamber A is a fuel charge control'mechanism for an eight-cylinder engine comprising eight metering orifices 23 receiving eight contoured metering rods 33 mounted on a carriage 34 for movement within the metering orifices 23. Each orifice separately controls the flow to eight separate fuel charging lines 24 which are connected with outlets 250 and 251 contained in the removable cap 252. Each separate fuel charging line 24 is, in turn, connected to an individual fuel nozzle 25 (as shown in FIG. 20) by way of the threaded connection 260. Preferabl there are as many metering orifices 23, metering rods 33, and fuel charging lines '24 connecting with nozzles 25 as there are cylinders in the internal combustion engine.

' The position of the carriage 34, and consequently the position of the metering rods 33, is determined by the position of shaft 36 through the magnetic clutch 35 (as shown in FIG. 8). Each of the clutch, elements consists of a small horseshoe magnet mounted for arcuate movement around concentrically located shafts such as 36 and 256 (shown in FIG. 13). Opposite poles of the magnets will be held adjacent by the force of attraction exerted through the non-magnetic removable plate 266 which lies between the adjacent magnets of clutch 35 and encloses the fuel chamber A.

Datum pressure metering.--Within the fuel metering part C is a metering orifice 55 (as shown in FIG. 15) controlled by a metering rod 87. The position of this rod the orifice determines the rate of flow from the chamber C to a distributing system for datum pressure. Thiscircuit has already been described as including a plurality of lines interconnecting outlet 270 with each of the fuel nozzles 25 through a suitable threaded connection 269 ('as shown in FIG.

Pressure in the distributing circuit for datum control is increased or decreased, as the case may be, by adjusting the area of the orifice 55 by the rod 87. The larger the area of the orifice, the greater will be the datum pressure, and vice versa.

' In order to avoid the friction inherent in pressure seals of one form or another, the position of the needle 87 is controlled by a magnetic clutch 86 (shown in FIG. 8), which has oppositely located magnets separated by the non-magnetic wall 280 sealing the chamber C. One of these magnets is carried on arm 69 of shaft 65 concentrically arranged with shaft 281 in FIG. '17. The position of the shaft .65 controls the-position of the rod 87, which, in turn, determines the size of the metering orifice 55, and therebythe pressure in the distributing system for datumpressure.

STRUCTURAL FORM OF ENGINE TEMPERATURE AND DE-ICING CIRCUIT As shown in FIG. 8, air for this circuit .enters by way of a port 111 in the top of the air conduit body B and travels by way of the passage 111 (shown in FIG. 11) into a thermostat chamber 106. Within the chamber is a thermostat coil 105 for operating a valve 114 controlling .a by-pass passage 112. The outlet of this passage is shown in FIG. 9 entering the heating passage 113 within the flange 201 of the air conduit body B. Chamber 106 has a cover shown in FIG. 12 and indicated as 280 within which is secured a nipple 107. A slotted projection 107a secured to the nipple receives a diametrically extending inner end of the thermostat coil 105. Suitable holes are provided in the cover for securing it to the main air, conduit body B.

Chamber 106 is connected by 107 with a suitable heater located in the water jacket or exhaust manifold, as the case may be, and the air passing through the heater is connected by way of a suitable threaded connection 110 (FIG. 9) with the heating passage 113. A branch 103 extends to the chamber 102 containing the thermostatic enrichment coil 76. Suction posterior of the throttle communicates with the chamber 102 by way of the passage 84 and the by-pass 101 in the cylinder 83. The operation of the load and temperature sensing means has already been described and will not be repeated here except to emphasize that its temperature response is effected by an engine temperature source in the manner above described.

Passage 113, which also receives heated air, as explained, is located adjacent the throttle 50 in the air conduit body B and discharges through a port 115 at the edge of the throttle.

14 W THROTTLE CONTROL SWITCH FOR FUEL CHARGE UNLOADER The end of the throttle shaft 51 in FIG. 11 carries an arm 98 integral with throttle lever 52, which moves as the throttle is opened to contact and close a switch 97, in substantially the wide-open throttle position. On the switch is a terminal 297 to which is connected the lead 96 of the circuit shown in FIG. 1. The body of the switch is connected to ground through the engine. induction system upon which the air conduit body B is mounted. When the switch is closed, the circuit is completed from the line 96 to ground through the engine.

In FIG. 9 is shown a connection 300 which leads to a spark port such as is conventional practice in the carburetor art, which port opens anterior of the throttle. The usual automatic vacuum controlled spark advance may be connected at 300.

ADJUSTMENT AND CALIBRATION In the system described, the metering rods 33 have certain limits of movement within the orifices 23 corresponding to the limits of angular movement for valve 37. Because of this feature and operation of the system at a selected pressure drop across orifices 23, calibration of the fuel metering is simplified.

All engine manufacturers determine the exact fuel requirements of their engines by test, and the results of these tests are represented by curves plotting fuel ratio against engine speed. One curve represents part-throttle fuel requirements or mixture ratio over the range of engine speeds at light load, such as to develop the power required at cruising speeds for an automobile. The other curve represents mixture ratio at full throttle throughout the range of engine speeds to develop full engine power. These curves are, generally speaking, parallel through a substantial range of engine speeds. Consequently, it is the usual practice to calibrate the metering for the fullthrottle curve with the step-up in action or effective. A suitable part-throttle curve is obtained with the step-up out of action. 4

This procedure applies to the present system. Metering rods 33 are first calibrated at a constant pressure drop to produce a varying rate of flow within the limits of their movement, which rate, when plotted, forms a curve corresponding in shape with the full throttle curve of the engine.

After rods 33 are properly profiled to give a rate curve shaped like the full throttle curve, then the pressure drop necessary to give the correct total flow required can be approximated. From the range in sizes for meter- 1ng rod 87 can be derived, and these applied by tapering the rod to include the entire range.

With this procedure completed, precise adjustments can be made in the fuel metering during engine operation. Referring to FIGS. 1 and 2, any fixed adjustment of screw 13, in turn, fixes the upper rich limits of the open throttle curve by adjustment of the limit of travel of rod 87 into or fice 55 to give the maximum pressure drop across onfices 23. For any given adjustment of screw 73, the adjustment of screw 72 will fix the lower lean limits for the part-throttle curve by limiting travel of rod 87 out of orifice 55 to give the minimum pressure drop at orifices 23. Actually, adjustments of the screw 73 result in raismg and lowering both the full and part-throttle mixture curves produced by those portions of the metering rods 33 having the same flow coefficient. Expressed another way, this ad ustment changes the mixture quality delivered at part-throttle and full-throttle, and maintains a constant difference in mixture quality.

If the flow coefficient varies at the idle end of the curve, which is possible, then adjustment of fuel flow can be made by screw 78 to elfect desired compensation.

Adjustments of the screw 72 result in varying dilferences between the two curves for mixture quality.

The above description of the action of the adjusting screws 72 and 73 on the datum pressure metering rod, and this, in turn, on pressure drop across orifices 23, will, of course, depend upon the pressure setting of datum discharge valve 60. This valve is preferably set to open initially at a lower pressure than the setting for the pressure regulator 22for example, 18 to 20 pounds gauge pressure. With this setting of valve 60, rod 87 has primary control of datum pressure during engine and pump operation. However, when the engine and pump stop, spring 85 expands, opening orifice 55. Pressures throughout the whole system will then equalize and gradually reduce to correspond with the pressure setting for initially opening valve 60. The balance in pressures cuts off the fuel flow in the engine charging circuit, and the valve 60 retains a substantial pressure to prevent vapor accumulation even at high under-hood temperatures.

Certain structures have been described herein which will fulfill all the objects of the present invention, but it is contemplated that other modifications will be obvious to those skilled in the art which come within the scope of the invention as defined by the appended claims.

I claim:

1. In a fuel metering device for an internal combustion engine, the combination with a fuel passage connected with said engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said; orifice a fluid pressure drop which is independent of, and not affected by, changes in engine speed, and a sensing means responsive to the rate of air flow to said engine for varying the area of said orifice with changes in air flow to the engine.

2. In a fuel metering device for an internal combustion engine, the combination with a fuel passage connected with the engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said orifice afiuid pressure drop which is independent of, and not affected by, changes in engine speed, and a sensing means responsive, at least in part, to throttle opening for varying the area of said orifice with changes in the rate of air flow to the engine.

3. In an engine charge forming system having an air conduit supplying air to the engine, a fuel passage connected with said engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, the combination of means for regulating the pressure downstream of said ori fice to maintain across said orifice a fluid pressure" drop which is independent of engine speed, and sensing means in said air conduit including a pivoted vane angularly positioned in response to the rate of air flow through said conduit by a substantially constant pressure differential across the vane connected to vary the area of said orifice as with changes in air flow to the engine.

4. In a fuel metering device for an internal combustion engine, the combination with a fuel passage connected with said engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said orifice a fluid pressure drop which is independent of, and not affected by, changes in engine speed, and a sensing means responsive in part to engine speed and in part to throttle opening for varying the area of said orifice with changes in air flow to the engine.

' 5. In a fuel metering device for an internal combustion engine, the combination with a fuel passage connected with said engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said orifice a fluid pressure drop which is independent of, and not affected by, changes in engine speed, a sensing means responsive in part to engine speed for varying the area of, said orifice with changes in air flow to the engine, and an engine load sensing means for said regulating means for increasing the pressure drop across said orifice.

6. In a fuel metering device for an internal combustion engine having a throttle controlled air intake, the combination with a fuel passage connected with said en gine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said orifice a fluid pressure drop, which pressure drop is independent of, and not alfected by, changes in engine speed and throttle openings, and a sensing means responsive to indicate rate of air flow for adjusting the area of said orifice as a desired function of at least one of said variables.

7. In a fuel metering device for an internal combustion engine having a throttle controlled air intake, the combination with a fuel passage connected with said engine, a variable area fuel metering orifice in said passage, and a pump for delivering fuel through said orifice to the engine, of means for regulating the pressure downstream of said orifice to maintain across said orifice a fluid pressure drop which is independent of, and constant with respect to such variables as changes in engine speed and throttle openings, a sensing means responsive to indicate rate of flow and throttle openings for adjusting the area of said orifice as a desired function of airflow, and engine load sensing means for said regulating means for increasing the pressure drop across said orifice.

8. In a fuel metering device for an internal combustion engine, the combination with a plurality of independently operating fuel passages for connection with the engine, an orifice in each of said passages, and a pump delivering fuel through said orifices to supply the engine through said passages, of means for varying the areas of said orifices calibrated at a constant pressure drop across said orifices to deliver fuel in proportion to the air flow to provide fuel-air ratios required by the engine throughout its speed range, and means in said device for selecting the degree of pressure drop across said orifices including a pressure regulator means for maintaining constant the pressure drop selected. v

9. In an engine charge forming system, the combination with an air conduit for engine charging air, a plurality of independently operating fuel passages for engine charging fuel, an..orifice in each of said passages, and a pump delivering fuel through said orifices to supply the engine through said passages, of means for varying the area of said orifices calibrated at a constant pressure drop across said orifices to deliver fuel in proportion to the air flow to provide fuel-air ratios required by the engine throughout its speed range, means responsive, in part to engine speed for controlling changes in orifice areas, pressure regulator means in said passages, and means to adjust said pressure regulator means to control the pressure drop across said orifices and therebythe rate of fuel flow to suit the fuel-air ratio requirements throughout the range of engine speeds.

10. In an engine charge forming system, the combination with an air conduit for engine charging air, a plurality of independently operating fuel passages for engine charging fuel, a variable area orifice in each of said passages, and a pump delivering fuel through said orifices to supply the engine, said orifices being calibrated at a constant pressure drop across said orifices to deliver fuel in proportion to the air flow to provide fuel-air ratios required by the engine throughout its speed range, means responsive, in part to engine speed for controlling changes in orifice areas, pressure regulator means in saidsystem Scleeiing the gree of pressure drop across said on- 17 fices and thereby the rate of fuel flow to suit the fuelair ratio requirements throughout the range of engine speeds, and means associated with said pressure regulator means for maintaining constant the pressure drop selected,

11. In an engine charge forming system, the combination with an air conduit for engine charging air, a fuel passage for engine charging fuel, an orifice in said passage, and a pump delivering fuel through said orifice to supply the engine, of means for varying the area of said orifice calibrated at a constant pressure drop across said orifice to deliver fuel in proportion to the air flow to provide fuel-air ratios required by the engine throughout its speed range, means responsive in part to engine speed controlling the changes in orifice area, means in said device for selecting the degree of pressure drop across said orifice and thereby the rate of fuel flow to suit the fuel-air ratio requirement thoughout the range of engine speeds, means controlled by said device for maintaining constant the pressure drop selected, and means for sensing changes in engine load to vary the pressure drop selected.

12. In a fuel metering device for an internal combustion engine having a throttle controlled air intake, the combination with a fuel passage for connection with the engine, an orifice in said passage, and a pump delivering fuel through said orifice to supply the engine, of means for varying the area of said orifice calibrated at a constant pressure drop across said orifice to deliver fuel in proportion to'the air flow to provide fuel-air ratios required by the engine throughout its speed range, means for regulating the pressure downstream of said orifice to maintain across said orifice a fluid pressure drop which isindependent of engine speed, and a sensingmeans responsive, at least in part, to changes in engine speed for varying the area of said orifice as a desired function of engine speed.

13. In a fuel metering device for an internal combustion engine, the combination with a fuel passage for connection with the engine, an orifice in said passage, and a pump delivering fuel through said orifice to supply the engine, of means for varying the area of said orifice calibrated at a constant pressure drop across said orifice to deliver fuel in proportion to the air flow to provide fuelair ratios required by the engine throughout its speed range, a sensing means responsive to airflow to the engine for varying the area of said orifice, a manual adjustment for selecting the degree of pressure drop across said orifice to obtain a rate of fuel delivery at one engine speed conforming to that required to obtain proper mixture for the rate of airflow indicated by said sensing means, and a pressure responsive device for maintaining constant the pressure drop selected.

14. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination of sensing means connected with the engine for indicating engine fuel requirements, a fuel metering orifice between said source and the engine, and means connected with and containing fuel under a pressure proportional to the source of fuel supply to said orifice and responsive to indications of said sensing means for selecting the degree of fuel pressure drop across said orifice to determine the rate of fuel fed to the engine, including means regulating the flow through said orifice controlled by said selecting means or maintaining constant the degree of fuel pressure drop selected regardless of fuel pressure fluctuations at the fuel pressure source.

15. In an engine charge forming system conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination of sensing means connected with the engine and rotatable to different angular positions for indicating engine fuel requirements in response to changes in engine load and engine temperature, a fuel metering orifice in said fuel supply, and means connected with and containing fuel having an air a to said orifice and responsive to the under a pressure proportional to thesource of fuel supply to said orifice and responsive to different angular positions of said sensing means for selecting the degree of fuelpressure drop across said orifice to determine the rate of fuel fed to the engine, said last means including means regulating the flow through said orifice controlled by said selecting means for maintaining constant the degree of fuel pressure drop selected regardless of fuel pressure fluctuations at the fuel pressure source.

16. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination of means for sensing certain engine variables including engine temperature to indicate engine fuel requirements, a variable metering orifice in said fuel supply, means for controlling said orifice in response to indications of one of said variables, and means connectedwith and containing fuel under a pressure proportional to the source of fuel supply to said orifice and responsive to the indications of other of said sensing means including said temperature sensing means for selecting the degree of fuel pressure drop across said orifice to determine the rate of fuel fed to the engine, said last mentioned means including a flow regulating means for said orifice controlled by said selecting means for maintaining constant the degree of fuel pressure drop selected regardless of fuel pressure fluctuations at the fuel pressure source.

17. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination of sensing means connected with the engine for sensing certain engine variables of engine operation indicating engine fuel requirements, including engine temperature and engine load, an indicator connected to said sensing means and positioned by opposing forces exerted by said sensing means, a fuel metering orifice in said fuel supply, and means connected with and containing fuel under a pressure proportional to that at the source of fuel supply position of said indicator for selecting the degree of fuel pressure drop across said orifice to determine the rate of fuel fed to the engine, said last means including a flow regulating means for said orifice controlled by said selecting means for maintaining constant the degree of fuel pressure drop selected regardless of fuel pressure fluctuations at the fuel pressure source.

18. In an engine charge forming system having a conduit supplying air to the engine and a pressurized fuel supply having a connection with the engine, the combination. of sensing means associated with the engine for indicating engine fuel requirements, means for adjusting the rate of fluid flow to the engine from said fuel supply, a datum pressure circuit pressurized from said fuel supply, means in said circuit forvarying the fuel pressure in said circuit in response to the indications of said sensing means and variations in fuel pressure in said supply, and means maintaining the fuel pressure in said connection proportional to datum pressure.

19. In an engine charge forming system having an'air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine including a pump, a fuel chamber, and a fuel distributing circuit supplied from said source, the combination of sensing means connected with the engine for indicating engine fuel requirements, a connection between said chamber and said fuel distributing circuit, a fuel metering orifice in said connection, a by-pass circuit connected to said chamber and said system anterior to said pump, flow control means for said by-pass circuit in said chamber for selecting the degree of fuel pressure drop across said orifice to determine the rate of fuel fed to the engine, flow regulating means for said orifice controlled by said selecting means for maintaining constant the degree of fuel pressure drop selected regardless of fuel pressure fluctuations at the pressure source, and a magnetic clutch for/transmitting indications of said sensing means outside said chamber to said flow control means inside said chamber.

20. In an engine charging system in combination, an air passage having a plurality of branches serving the engine cylinders, a throttle means controlling the flow of air through said passage, a fuel passage having an outlet in each of said branches, hydraulically controlled valve means for regulating the flow of fuel from each of said outlets, means responsive in part to engine speed hydraulically connected to urge said means open, and means responsive to air pressure, changes in said air passage downstream of said throttle means and hydraulically connected to urge said valve in .a closing direction.

21. In an engine changing system in combination, an air passage having a plurality of branches serving the engine cylinders, throttle means controlling the flow of air through said passage, a fuel passage having an outlet in each of said branches, hydraulically controlled valve means for regulating the flow of fuel from each of said outlets, means responsive at least in p ant to throttle movement hydraulically connected to urge said valve means open, and means responsive to air pressure changes in said air passage downstream of said throttle means and hydraulically connected to urge said valve in a closing direction.

22. In an engine charging device, in combination, an air passage, throttle means controlling the flow of air through said passage, a fuel passage, valve means actuated solely by fuel pressure for controlling the flow of fuel therethrough, means responsive to the air flow in said air passage hydraulically connected to said valve means, and means responsive to air pressure changes in said air passage downstream of said throttle means hydraulically connected to said valve means and effective upon increase in air pressure to operate said valve means to increase the flow of fuel through said passage.

23. A device for supplying fuel to an engine comprising an air supply passage, a throttle in the passage for controlling the supply of air, a fuel pump, a connection for supplying fuel from the pump to the engine, a valve for varying the fuel supplied through the connection, means for urging said valve in a direction to increase the fuel rupply with a force which increases with increase in air low to the engine, means for urging said valve in a direcion to decrease the fuel supply with a force that is contant with respect to said first force and independent of uel flow to the engine, whereby substantially constant uel-to-air proportioning is maintained, and means for modifying one of said forces under certain conditions of ngine operation for varying the proportions of fuel and ir supplied to the engine.

24. In a charge forming system for an internal comustion engine having a plurality of cylinders each with n air intake pipe, a fuel system comprising a fuel disibuting circuit, means for regulating the total fuel flow [id for feeding said fuel under pressure to said fuel .rcuit, a fuel discharge valve for discharging fuel into ach air intake pipe, each of said valves having its inlet de connected to said fuel distributing circuit and being lapted to continuously discharge fuel therefrom into l associated air intake pipe, valve operating means for LC]: of said valves, each said valve operating means Lving one side responsive to the pressure of the fuel pplied to the inlet side of its associated valve for urging id valve in an opening direction, liquid passage means terconnecting the opposite sides of said valve operating cans, and means for maintaining a predetermined con- )lled fluid pressure in said liquid passage means acting th equal force on each of said valves whereby uniform e1 flow is obtained from each of said valves.

25. In an induction system for an internal combustion gine, the combination of a throttle controlled air pas- ;e leading to said engine, a passage supplied with fuel pump pressure, a charging fuel distributing circuit suped from said fuel passage and delivering fuel to said air passage, a variable area orifice in said fuel passage and a pressure regulating means'to maintain across said orifice a pressure drop which is independent of engine speed including a second fuel distributing circuit supplied from said fuel passage, means for establishing a datum fuel pressure in said second distributing circuit proportional to that in said fuel passage, a fuel flow regulating valve controlling the discharge from said charging fuel distributing circuit and regulated by oppositely acting fuel pressures through connections with said charging fuel distributing circuit pressure and datum pressure, and sensing means responsive in part to engine speed changes for varying the area of said orifice as a desired function of air flo'wthrough said air passage.

26. In an induction system for an internal combustion engine, the combination of a throttle controlled air passage leading to said engine, a passage supplied with fuel at p ump pressure, a charging fuel distributing circuit supplied from said fuel passage and delivering fuel to said air passage, a variable area orifice in said distributing circuit and a pressure regulating means to maintain across said orifice a pressure drop which is independent of engine speed, including a second fuel distributing circuit supplied from said fuel passage, means for establishing a datum fuel pressure in said second distributing circuit pro portional to that in said fuel passage, lating valve controlling the discharge from said charging fuel distributing circuit and regulated by oppositely acting fuel pressures through connections with said charging fuel distributing circuit pressure and datum pressure, and sensing means responsive at least in part to throttle opening for varying the area of said orifice as a desired function of air flow to the engine.

27. In a charge forming system for an internal combustion engine having a plurality of cylinders, each with an air intake pipe leading from a common inlet, a fuel supply system having a pressurized source of fuel, and a distributing circuit for engine charging fuel leading from said source and discharging into each intake pipe, the combination of variable area fuel metering orifice means for said circuit for engine charging fuel, a sensing means in said inlet for indicating the rate of air flow to the engine, means for varying the area of said orifice means in response to indications of said sensing means, means for sensing varying fuel requirements of the engine at different loads and engine temperatures, a datum pressure distributing circuit, means for maintaining a pressure in said datum circuit porportional to that in said distributing circuit for engine charging fuel, means for varying the datum pressure in response to indications of said second sensing means, and means for controlling the discharge of fuel thro gh said variable orificem eans, comprising valve means downstream from said variable orifice means responsive to the dilference in pressures between the distributing circuit for engine charging fuel and the distributing circuit for datum pressure.

28. In a fuel flow regulating means for an engine induction system comprising in combination a common source of fuel, a main discharge conduit leading from said source to a plurality of branchconduits, and outlet for eachbranch conduit in the engine induction system, a fuel pump in said main conduit, a variable restriction in each of said branch conduits, a valve in each of said branch conduits downstream from its associated restriction, operating means for each valve including a pair of chambers separated by a movable wall, means connecting one of each of said pairs of said chambers to itsassociated branch conduit between the restriction and the valve therein so that the pressure in said one chamber acts on said wall in a valve opening direction; a by-pass conduit connected to said main discharge conduit and the inlet to said pump, means for establishing a datum pressure in said by-pass conduit proportional to the pressure in said main conduit, means connecting the other chambers of all of said operating means to said by-pass a fuel flow reguconduit so that the valves are operated to maintain equal pressures on the downstream sides of all said variable restrictions, and means responsive to an engine operating condition for controlling all of said variable restrictions.

29. A fuel distributing apparatus for an engine charging system comprising in combination, an air induction system leading from a common inlet to each of a group of the cylinders of the engine, a pump for supplying fuel under pressure, a main discharge conduit leading from said pump to a plurality of branch conduits, outlets for said branch conduits in the engine induction system, a fuel metering restriction for each of said branch conduits, a valve in each of said conduits downstream from its associated restriction, operating means for each of said valves including a pair of chambers separated by a movable wall operating each valve, one of each pair of said chambers being connected to its associated branch conduit between the restriction and the valve therein so that pressure in said one chamber acts on said wall in a valve opening direction, a by-pass conduit connected between said main discharge conduit and the inlet of said pump, means for establishing a datum fuel pressure in said by-pass conduit, said means including a variable restriction at the inlet of said by-pass conduit and a flow restriction at the outlet of said by-pass conduit, means connecting the other chambers of all of said valve operating means to said by-pass conduit between said restructions so that the valves are operated to maintain equal pressures on the downstream sides of all of said fuel metering restrictions, and means responsive toan engine operating condition to operate said variable restrictions and thereby vary the flow uniformly through each of said valves.

30. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel to supply the engine, the combination of means for sensing certain engine variables including engine temperature and engine load, a movable indicator connected to said sensing means and positioned by the balanced reaction of opposing forces exerted by said sensing means on said indicator, and means for regulating the fuel pressure for. supplying the engine controlled by positions of said indicator.

31. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination differential across the vane connected to vary the area of said orifice, and means providing for adjustment of these angular indications of the vane in response to rate of air flow, including an air by-pass around said vane, and means for adjusting the flow through said by-pass.

34. An engine charge forming system having an air conduit supplying :air to the engine, a throttle valve therein, and a pressure source of fuel, a fuel nozzle supplied from said source and discharging into said engine and valve means between said source and said nozzle, and an actuator for said valve means operated in response to opening movement of said throttle for closing said valve means when the engine is cranked, to reduce fuel delivery from said nozzle. 1

35. An engine charge forming system having a throttle controlled air conduit supplying .air to the engine, a fuel pressure source, a differential pressure operated fuel nozzle discharging into said engine, an engine charging distributing circuit connecting said source with said nozzle,

a datum pressure distributing circuit connecting said source and said nozzle, and valve means in said datum pressure distributing circuit closed by opening movement of said throttle for increasing said datum pressure to reduce the discharge of fuel from said nozzle when the engine is cranked. V

36. An engine charge forming system having a throttle controlled air conduit supplying air to the engine, a fuel pressure source, a differential pressure. operated nozzle discharging into said engine, an engine charging distributing circuit connecting said source and said nozzle, 3. metering means for said distributing circuit to measure the flow therethrough, a datum pressure distributing circuit connecting said source and said nozzle, and a valve in said datum pressure distributing circuit closed by opening of said throttle for increasing the datum pressure to reduce the discharge from said nozzle below the metered rate when the engine is cranked.

37. An engine charge forming system for use on an internal combustion engine having a starter motor, a power source for said motor, and a control meansbetween said source and said motor for energizing the motor to crank the engine, said system comprising, in combination, a throttle controlled air conduit supplying air to the engine, a fuel pressure source, a differential pressure operated nozzle discharging into said engine, an engine charge distributing circuit connecting said source and of two means for sensing certain engine variables, an

indicator connected to both said sensing means and positioned by opposing forces exerted by said sensing means, a variable lost motion connection between one of said sensing means and said indicator, and means for regulating the flow of fuel for supplying the engine controlled by positions of said indicator.

32. In an engine charge forming system having an air conduit supplying air to the engine and a pressurized source of fuel for supplying the engine, the combination of means for sensing certain engine variables including engine temperature and engine load, an indicator connected to said sensing means and positioned by opposing forces exerted by said sensing means, a variable lost motion connection between one of said sensingmeans and said indicator, a device for adjusting the effect of said temperature sensing means on said indicator in the normal range of engine operating temperatures, and means for subsequently controlling the flow of fuel for supplying the engine in response to the positioning of said indicator by changes sensed in engine load.

33. In an engine charge forming system having an air conduit supplying air to the engine, a fuel passage connected with said engine, a .variable area fuel metering orifice in -said passage, and a pump for delivering fuel through said orifice to the engine, the combination of a sensing means for indicating the rate of air flow in said air conduit comprising a pivoted vane angularly positioned in response to a substantially constant air pressure said nozzle, metering means for said distributing circuit to measure the flow therethrough, a datum pressure distributing circuit connecting said source and said nozzle, and a valve in said datum pressure distributing circuit closed by opening of said throttle during cranking of the engine to increase the datum pressure to reduce the discharge from said nozzle below the metered rate.

38. In an engine charge forming system having a throttle controlled air conduit supplying air to the engine, a pressurized source of fuel for supplying the engine, fuel metering means in said fuel supply, and temperature responsive sensing means for varying the fuel flow through said metering means, the combination of means for operating. said sensing means including a source of heat on said engine, a heating circuit betweer said source and said sensing means including a by-pas: around said source of heat, means for causing a circulation of fluid through said circuit, and temperature respon sive means for controlling the operation of said by-pass 39. In an engine charge forming system having a throt tle controlled air conduit supplying air to the engine a pressurized source of fuel for supplying the engine, fue metering means in said fuel supply, and enginl temperature responsive sensing means for varying th fuel flow through said metering means, the combinatioi of means for operating said sensing means comp-risin a source of heat on said engine, a heating circuit extendin from said source through said air conduit adjacent sail throttle to said sensing means, a by-pass for said heatin 23 circuit extending around said source of heat and dis charging directly into said heating circuit in said air conduit, means for causing a circulation of fluid flow through said circuit and said by-pass, and temperature responsive means for controlling the operation of said by-pass.

40. An engine charge forming system comprising, in combination, an engine condition sensing means for sensing engine fuel requirements, indicator means positioned by the condition sensed by said sensing means, a fuel feeding device connected to the engine having a pressurized chamber, a fuel metering device in said chamber having a movable part for varying the quantity of fuel metered, a non-magnetic wall in said chamber adjacent said movable part and said indicator, and a magnetic clutch with magnetic elements connected to said movable part within said chamber and connected to said indicator means outside said chamber whereby said sensing means directly controls fuel metering.

41. In an engine charging system having an air con- :luit to supplyair to the engine and a pumpfor supplying fuel to the engine, the combination of a device saving a chamber supplied from said pump, means for proportioning the rate of fuel flow through said chamber the rate of air how to the engine through said coniuit, and a flow divider receiving the fuel flow from ;aid proportioning device and delivering the fuel at the 'ate received to a plurality of discharge points in the :ngine, comprising a plurality of fuel passages branching 'rom said chamber for conducting'the fuel to said points )f discharge, a calibrated metering restriction in each lf said branch fuel passages upstream of each of said )oints of discharge, a regulating valve in each fuel passage [ownstream of each metering restriction, said chamber eing common to said fuel passages for maintaining the ressure upstream of said restriction substantially equal 1 all of said passages, a movable wall connected to each f said valves, each said wall being subject on one side iereof to the fuel passage in its associated fuel passage ownstream of the restriction in said passage to apply force to said wall in a direction tending to open said alve, means for conducting a regulating fluid under ositive pressure to the opposite side of each of said 'alls to apply equal forces in a direction tending to close rch of said valves and thereby maintain the pressure awnstream of said restrictions at a value proportional the pressure of said regulating fluid to render the ow of fluid to said points of discharge equal and proporonal to the equal drop across said restrictions, and means )ntrolling the pressure of the regulating fluid so as to 'edetermine the fuel pressure downstream of each of id restrictions to eliminate the effect of pressure fluctua- )IlS downstream of said orifices on the rate of fuel flow each of said points of discharge.

42. In an automatic flow regulating system for fluids,

fuel chamber adapted to receive and hold the fluid to regulated under pressure, said fuel chamber having plurality of conduits branching therefrom for conductg the fluid to points of discharge, a variable area meterg restriction in each of said branch conduits upstream each of said points of discharge, control means opera- 'e for simultaneously varying the flow areas of said :tering restriction, an equalizing valve in each conit downstream of each variable area metering restricn, said fuel chamber being common to said branch nduits for maintaining the pressure upstream of said riable area restrictions substantially equal for all conits, a movable wall connected to each of said valves,

:h said wall being subjected on one side thereof to pressure of fluid in its associated conduit downearn of the metering restriction therein, means for iducting a regulating fluid to the opposite side of each d wall, and means acting independent of said first :ntioned control to maintain the regulating fluid under ssure proportional to said fuel chamber pressure to :reby maintain the pressure downstream of said variable area restrictions at a given value or values in all conduits and thereby render the flow of fluid to said discharge points proportional to the change in area of said metering restrictions.

43. A fuel distributing apparatus for a pressurized charge forming system of an engine having a plurality of combustion chambers comprising, in combination, an air induction system leading to each of the combustion chambers of the engine, a sensing means in said induction system for indicating the rate of airflow to the engine, a fuel chamber in the charge forming system containing the fuel under pressure to be regulated, a pump for supplying fuel under pressure to said fuel chamber, said fuel chamber having a plurality of conduits branching therefrom for conducting fuel to points of discharge communicating with the combustion chambers, a variable area metering restriction in each of said branch conduits upstream of the point of discharge thereof, control means actuated by said rate of airflow sensing means for simultaneously and equally varying the flow areas of said metering restrictions, an equalizing valve in each branch conduit downstream of the variable area metering restriction therein, said fuel chamber being common to said branch conduits for maintaining the pressure upstream of said variable area restrictions substantially equal for all conduits, a movable wall connected to each of said valves, each said well being subjected on one side thereof to the pressure of fluid in its associated conduit downstream of the restriction in said conduit, means for conducting regulating fluid from said fuel chamber to the opposite side of each said wall, and means independent of said first mentioned control to maintain the regulating fluid under pressure proportional to said fuel chamber pressure to thereby maintain the pressure downstream of said variable area restrictions at a given value or values in all conduits and render the flow of fluid to said discharge points proportional to the change in area of said metering restrictions.

44. Fuel flow regulating means for an engine induc tion system comprising, in combination, a main discharge conduit leading to a plurality of branch conduits, an outlet for each branch conduit in the engine induction system, a fuel pump for supplying fuel under substantially constant pressure to said main discharge conduit, a fuel metering means of variable flow capacity in each of said branch conduits, engine operated means for varying the capacity of each of said fuel flow metering means simultaneously and equally, a valve in each of said branch conduits downstream from its associated metering means, operating means for each valve including a pair of chambers separated by a movable wall, means connecting one of each of said pairs of said chambers to its associated branch conduit between the restriction and the valve therein so'that the pressure in said one chamber acts on said wall in a valve opening direction; a datum pressure system, means independent of said engine operated fuel flow metering means for establishing a datum pressure in said datum pressure system proportional to the pressure in said'main discharge conduit and independent of said engine operated fuel flow metering means, and means connecting the other chambers of all of said valve operating means to said datum pressure system so that the valves are operated to maintain equal pressures on the downstream sides of all of said variable restrictions at a constant pressure drop relative to the pressure in said main discharge conduit so as to maintain equal flows in said'branch conduits varying'directly with changes in flow capacity of said fuel metering means.

'45. In an engine charge forming system having a branched air conduit leading from a common air inlet to each of a group of engine combustion chambers, the combination of a pump for supplying fuel underpressure, a distributing circuit for engine charging fuel supplied form said pump and including a fuel chamber with a plurality of branch conduits supplying fuel to said combustion chambers, a fuel metering restriction for each of 

